None.
Not Applicable.
The present invention relates to an adapter and method for mounting vehicle wheels to the spindle shaft of a vehicle wheel balancer, and more particularly, to a multi-jawed chuck adapter configured to seat about the spindle of a vehicle wheel balancer and to facilitate the mounting of vehicle wheels thereon with a reduction in the number of error sources.
Traditionally, as seen in prior art FIGS. 1 and 2, an automotive vehicle wheel assembly 10, with or without a tire secured to the wheel, is mounted onto the spindle 12 or rotatable shaft of a wheel balancing machine (not shown) by centering the wheel and tire assembly 10 on a cone 14 fitted around the spindle 12, and clamping the wheel and tire assembly 10 in place by means of a pressure ring 15 and wing nut 16 or similar retainer. Such a system is described in U.S. Pat. No. 4,168,627 to Held et al., and may include a spring (not shown) exerting a force on a spring bias plate 18 contained within a hub 19 to further aid in seating the cone 14 into the wheel and tire assembly 10.
It has been found that the traditional cone 14 and wing nut 16 mounting systems do not work well with large wheel and tire assemblies 10, such as those from pickup trucks, recreational vehicles, or commercial trucks which are heavy, and include an offset wheel rim. When mounting wheel and tire assemblies 10 from such vehicles, typically it is difficult to properly seat the wheel and tire assembly on the cone 14 such that the wheel and tire assembly is centered properly. An improper centering of the wheel and tire combination 10 can induce errors during the balancing operation.
Difficulties in mounting the large wheel and tire assemblies 10 to the traditional cone 14 arise from the fact that the center of gravity of the wheel and tire assembly 10 typically lies in a vertical plane which differs substantially from the vertical plane defined by the rim mounting surface containing the wheel pilot hole into which the cone 14 seats. The heavy weight of the wheel and tire assembly 10 and the substantial offset between the wheel pilot hole and the center of gravity of the wheel and tire assembly 10 causes the wheel and tire assembly 10 to twist as it is mounted to the cone 14, and prevents proper placement on the cone 14, resulting in the wheel and tire assembly 10 being mounted in an eccentric or non-concentric position to the wheel balancer spindle 12. It has been found that this eccentricity can be marginally improved if the wheel and tire assembly 10 is manually lifted in an upward direction while the wing nut 16 is tightened, thereby permitting the axial forces exerted by the wing nut 16 to shift the position of the wheel and tire assembly 10 on the cone 14. However, such wheel and tire assemblies 10 are heavy.
An additional source of error introduced to the wheel balancer system by the traditional cone 14 and wing nut 16 clamping method is the contact surface between the wheel 10 and cone 14. While the axial pilot hole 20 of a vehicle wheel is generally coaxial with the wheel axis of rotation, the wheel pilot hole 20 often includes a chamfered edge, ground in during the manufacture process to break the sharp comer of the pilot hole 20. This chamfer is not ground to any specific dimension or tolerance, and therefore cannot be assumed to be concentric with the wheel axis of rotation passing through the pilot hole 20. When the wheel and tire assembly 10 is placed onto the cone 14 of a traditional balancer mounting system, the surface of the cone 14 contacts the surface of the chamfer, not the pilot hole 20 edge. Therefore, any runout or eccentricity in the chamfer results in an eccentric mounting of the wheel and tire combination 10 to the balancer spindle 12 which can adversely affect balancing operations.
Several variations on the traditional cone mounting system have been employed to improve the accuracy of mounting wheel and tire assemblies to the balancer spindle 12. Cones 14 having narrow taper angles such as 10xc2x0 to 20xc2x0 have been found to improve the mounting of large wheel and tire assemblies 10 over cones 14 having larger taper angles such as 45xc2x0 to 60xc2x0. However, a larger number of narrow taper angle cones is required to correspond to the wide variation in wheel pilot hole 20 sizes, and the inherent difficulties associated with eccentric mounting of the wheel and tire assembly 10 remain.
As seen in FIG. 2, an additional variation includes the use of a flange plate adapter 22 M with the cone 14 mounted on the balancer spindle. The flange plate adapters 22 are illustrated in U.S. Pat. No. 4,423,633 to Coetsier. Flange plates adapters 22 commonly include rigid pins 24 with conical ends 26 for positioning within the lug nut openings 28 of a wheel to improve centering of the vehicle wheel about the balancer spindle axis 12. While the use of flange plate adapters 22 may provide some improvement in reducing eccentric mounting of the vehicle wheel and tire assembly 10, several problems remain. First, the vehicle wheel must still be lifted into place prior to securing the flange plate adapter 22. This is a difficult operation. The addition of the flange plate adapter 22 about the spindle axis 12 introduces an additional source of error, as the flange plate adapter 22 and the cone 14 may not be concentric with respect to each other. As with the chamfered edge of the wheel pilot hole 22, the lug nut holes 28 of a vehicle wheel are often chamfered as well, leading to a source of error when the flange plate pins 24 are seated therein. Furthermore, the chamfers of the lug nut openings 28 are not always concentric with the lug nut openings. Under these conditions, the flange plate adapter 22 itself can be forced to deform as the wing nut 16 is tightened to retain the wheel and tire assembly 10 on the balancer spindle 12.
Accordingly, there is a need in the wheel balancer industry for an apparatus and method to facilitate the mounting of large vehicle wheel and tire assemblies 10 onto the spindle shaft 12 of wheel balancer machines.
Among the several objects and advantages of the present invention are:
The provision of a multi-jawed chuck configured to seat within the pilot hole of a vehicle wheel or wheel assembly and to facilitate mounting of the vehicle wheel or wheel assembly to the spindle shaft of a balancer without the use of a mounting cone;
The provision of the aforementioned multi-jawed chuck wherein the chuck has three expandable and retractable jaws for contacting the inner surface of a vehicle wheel pilot hole;
The provision of the aforementioned multi-jawed chuck wherein the chuck is self-centering within the wheel pilot hole;
The provision of the aforementioned multi-jawed chuck wherein the chuck is configured for attachment to the vehicle wheel prior to placement of the vehicle wheel on a wheel balancer spindle shaft;
The provision of the aforementioned multi-jawed chuck wherein mounting errors associated with chamfered edges of the vehicle wheel pilot hole are minimized;
The provision of the aforementioned multi-jawed chuck wherein the chuck is self-centering within a wide range of vehicle wheel pilot holes;
The provision of the aforementioned multi-jawed chuck wherein use of the multi-jawed chuck provides for a high degree of repeatability in vehicle wheel balancing operations;
The provision of the aforementioned multi-jawed chuck wherein use of the multi-jawed chuck eliminates the need to lift the vehicle wheel while tightening the wing nut to retain the vehicle wheel upon the balancer spindle shaft; and
The provision of the aforementioned multi-jawed chuck wherein accuracy of wheel balancing operations is improved.
Briefly stated, the multi-jawed chuck of the present invention comprises a cylindrical body having a central bore, sized to fit with close tolerances about the spindle of a wheel balancer machine. The multi-jawed chuck includes a number of jaws located on one face, configured to expand and contract radially outward from the axis of the central bore. Each jaw includes at least one flange for contacting the inner surface of a wheel pilot hole.
During use, a wheel and tire assembly to be balanced is typically placed horizontally on a floor or other suitable surface such that the wheel pilot hole is accessible for installation of the multi-jawed chuck. The multi-jawed chuck is positioned such that the jaws pass through the wheel pilot hole. Once positioned, the jaws of the multi-jawed chuck are simultaneously moved radially outward to forcefully engage the inner surface of the wheel pilot hole, centering and holding the chuck therein. With the multi-jawed chuck firmly secured in the pilot hole of the wheel, the wheel and tire assembly is lifted and placed on the spindle shaft of the wheel balancer machine by fitting the axial bore of the multi-jawed chuck onto the spindle shaft. Once the wheel and tire assembly is seated on the spindle shaft by means of the multi-jawed chuck, a traditional wing nut is threaded on to the exposed end of the balancer spindle shaft and tightened against the exposed face of the wheel, thereby securing the wheel and tire assembly for balancing operations be seating the back face of the chuck against the hub. Another way to use the chuck is to place a spacer against the hub first, and install the multi-jawed chuck on the convex side of the vehicle wheel.
The foregoing and other objects, features, and advantages of the invention as well as presently preferred embodiments thereof will become more apparent from the reading of the following description in connection with the accompanying drawings.